Hey Markus,
"This radio requires +90, +67.5, and +22.5 volts for the various stages"
Where did you get that information from?
There are different versions of this radio however the one I have requires +90Volt DC, +20 volt DC (Really 22.5), and 6Volts DC. You can easily Run the B+ voltages off of a string of 9Volt Batteries. Theoretically a set of Duracell 9volts will last over 40hrs of playing time. The Filaments are 5volts but the radio has a rheostat and resistors to drop the voltage from a 6 volt battery. I do recommend using a 6 volt power supply rather than a batter only because the 5 tube will draw as much as 1 1/4 amps total.
Another note. The filaments in these tube must be run off of DC, and well filtered DC or you will get a tremendous amount of hum. Tubes that will run off of AC on the filaments had not even been invented when this radio was designed.
“should that faceplate be 'atwater kent' green ? I KNOW it shouldn't be RED ”
This radio faceplate should be Brown. Antique Electronics Supply used to sell a crinkle finish in Van Dyke Brown which is pretty close to the original. They probably still do.
“actually, this is my neighbor's radio, which I plan on get singing again - he has a similar era Peerless speaker just like this”
This would have originally been used with a Horn type speaker similar to this one.
However, that Peerless is no too far off. If it has continuity it would work just fine. Take a 1 ½ volt battery and drag the lead across and see if you can get some noise out of it.
Also, this radio was designed to utilize a high impedance speaker. If you try and use a modern speaker you will need to add an output transformer to the circuit.
Now generally speaking this is a 5 tube TRF (tuned radio frequency) radio. Each of the RF coils is individually tuned by a separate knob and thus this type of radio is also known as a “3 dialer”. This was the most popular configuration of that time period and you have to tune them one at a time in general lock step to tune in a station. Before you spend a lot of effort on it get a ohm meter and check the audio transformers. They are notorious for being open. You can replace them but finding the original AK cylinder
Once you get it running you’ll probably be surprised how many stations you can pick up with it. AK actually made very functional, well performing, and affordable radios.
You can find the schematics here
http://www.nostalgiaair.org/Resources/042/T0000042.htm
Should be enough for now. If you have any question feel free to ask. You should be able to easilily find the missing tube. If not drop me a PM as I have plenty of spares I'd be willing to part with.
Steve